U.S. patent number 6,793,286 [Application Number 10/253,777] was granted by the patent office on 2004-09-21 for chair adjustment mechanism.
This patent grant is currently assigned to HON Technology Inc.. Invention is credited to Ralph C. Burgin.
United States Patent |
6,793,286 |
Burgin |
September 21, 2004 |
Chair adjustment mechanism
Abstract
A simple, inexpensive and reliable chair adjustment mechanism is
disclosed. The mechanism includes a base which is fastened to a
chair support, a slide attached to an assembly to be adjusted, such
as a back or a seat or arms, and a spring device cradled by the
base for engaging one of a series of spaced ramps integral with the
slide. The slide also includes ramps for pushing the spring device
into an out-of-the-way position secured to two hooks on the base so
that at the end of the slide's extension it may be returned to a
retracted position in one easy movement. When reaching the
retracted position, other ramps push the spring device out of the
engagement with the hooks so that the spring device extends through
a space between the base and the slide to again selectively engage
the series of spaced ramps.
Inventors: |
Burgin; Ralph C. (West Point,
IA) |
Assignee: |
HON Technology Inc. (Muscatine,
IA)
|
Family
ID: |
23262969 |
Appl.
No.: |
10/253,777 |
Filed: |
September 24, 2002 |
Current U.S.
Class: |
297/353;
297/411.36 |
Current CPC
Class: |
A47C
7/402 (20130101) |
Current International
Class: |
A47C
7/40 (20060101); B60N 002/02 () |
Field of
Search: |
;297/353,411.36,411.57
;248/118 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cuomo; Peter M.
Assistant Examiner: Harris; Stephanie
Attorney, Agent or Firm: Golant; Joseph H. Jones Day
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
The present application relates to Provisional Application No.
60/324,295 filed Sep. 25, 2001. This application claims the filing
date of the above-identified provisional application as a priority.
Claims
What is claimed is:
1. A chair adjustment mechanism comprising: a base adapted to be
attached to a chair, said base having a hook; a slide connected to
said base, said base and said slide being relatively movable
between a retracted position and an extended position and said
slide having an abutment wall; a space formed between said base and
said slide; a plurality of structures extending between said base
and said slide in said space, each of said plurality of structures
having an abutment surface for lockingly positioning said slide
relative to said base in intermediate positions between said
retracted position and said extended position; a spring having two
legs, a central body and a head mounted in said space, said head
for flexing said central body, said central body for engaging
selectively said plurality of structures, and said two legs for
limiting movement of said slide relative to said base; a first high
structure extending into said space for flexing said central body
when said extended position is reached and for causing said central
body to slide and become engaged and restrained by said hook, and
for causing said legs to engage said abutment wall of said slide
and stop movement of said slide relative to said base wherein said
central body is not able to engage said plurality of structures;
and a second high structure extending into said space for sliding
and disengaging said central body from said hook when said
retracted position is reached wherein said central body is
thereafter able to engage said plurality of structures.
2. The apparatus as claimed in claim 1 wherein: said plurality of
structures is a series of ramps and said series of ramps is
connected to said slide.
3. The apparatus as claimed in claim 2 wherein: said spring device
is cradled by said base.
4. The apparatus as claimed in claim 3 wherein: said first high
ramp and said second high ramp are connected to said slide.
5. The apparatus as claimed in claim 2 wherein: said first high
ramp and said second high ramp are connected to said slide; and
said spring device includes a first abutment surface for engaging
selected ramps.
6. The apparatus as claimed in claim 1 wherein: said spring
includes a first abutment surface for engaging selected structures
of said plurality of structures.
7. The apparatus as claimed in claim 1 wherein: said plurality of
structures includes three columns of ramps aligned on said slide;
said first high structure includes a first group of three high
ramps positioned at the bottom of said three columns of ramps; and
said second high structure includes a second group of three high
ramps positioned at the top of said three columns of ramps.
8. The apparatus as claimed in claim 7 wherein: said abutment wall
includes two abutment walls formed at a lower porion of said base;
and said hook includes two hooks formed at an upper portion of said
base; and a space on said base for mounting the spring adjacent
said two hooks.
9. The apparatus as claimed in claim 8 wherein: said two legs of
said spring include abutment surfaces for engaging said two
abutment walls; said central body includes three abutment surfaces
for selectively engaging ramps of said ramps in said three columns;
and said central body includes two shoulders for engaging said
hooks.
10. The apparatus as claimed in claim 9 including: an abutment
block formed on said base; and wherein said central body includes a
ledge for engaging said abutment block.
11. The apparatus as claimed in claim 10 wherein: said three
abutment surfaces of said central body are formed on an opposite
side of said central body from said ledge.
12. The apparatus as claimed in claim 11 wherein: said base is an
integral molded structure; and said slide is an integral molded
structure.
13. A chair adjustment mechanism comprising: a first structure
connected to a chair and having a hook, a ledge and an abutment
wall; a second structure connected to move relative to said first
structure between an extended position and a retracted position and
having three columns of protrusions including a series of small
protrusions, a first group of large protrusions at the top of said
columns and a second group of large protrusions at the bottom of
said columns; and a third structure having a leg, a central body
and a head, said third structure being mounted to slide between
said hook and said ledge; and wherein between extended and
retracted positions said central body selectively engages said
series of small protrusions; at said extended position, said third
structure engages said first group of large protrusions, said leg
engages said abutment wall to stop relative movement of said first
and second structures and said third structure slides and flexes to
engage and be restained by said hook so as to prevent said central
body from engaging said series of small protrusions; and at said
retracted position, said third structure engages said second group
of large protrusions and is disengaged from said hook and said
third structure slides to engage said ledge and flexes so as to be
able to engage said series of small protrusions.
14. The apparatus as claimed in claim 13 wherein: said protrusions
are ramps.
15. The apparatus as claimed in claim 14 wherein: said central body
of said third structure includes three abutment surfaces for
engaging said ramps.
16. The apparatus as claimed in claim 15 wherein: said central body
of third structure includes a ledge for engaging the ledge of said
first structure.
17. The apparatus as claimed in claim 16 wherein: said central body
includes a shoulder for engaging said hook.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a chair adjustment mechanism and,
more particularly, to a mechanism which can conveniently be
operated to selectively adjust a seat, back or arm relative to a
chair support structure, the mechanism being simple, inexpensive
and reliable.
2. Description of Related Art
Many forms of back adjustment mechanisms are known, particularly
for chairs used in office environments. Often, it is desirable to
adjust the vertical height of a chair back for the comfort of the
user as the user is engaged in various office-related tasks. The
same is true of a chair seat and a chair arm. One such chair back
adjustment mechanism, for example, which is well-known in the art,
is a simple slide mechanism which moves vertically on a chair back
support, usually comprising one or two tubes, with a manually
tightened knob that can lock the back in a predetermined vertical
position relative to the chair seat.
While such chair adjustment mechanisms have proved to be reliable
and economically manufacturable to produce, it is desirable to
provide an improved mechanism which is cost-effective to produce
and provides increased convenience to the chair user.
SUMMARY OF THE INVENTION
The difficulties encountered with previous devices have been
overcome by the present invention. What is described here is a
chair adjustment mechanism comprising a base adapted to be attached
to a chair in a fixed position, a slide connected to the base and
movable between a retracted position and a fully extended position
in relation to the base, the slide being guided by the base, a
space formed between the base and the slide, a series of ramps
connected to extend between the base and the slide in the space for
lockingly positioning the slide in intermediate positions between
the retracted position and the fully extended position, a spring
device mounted between the base and the slide and capable of
engaging the series of ramps, the spring device being flexed
between two positions, a first position wherein the spring device
makes selective contact with individual ramps of the series of
ramps and a second position wherein the spring device is able to
avoid engagement with the ramps of the series of ramps, a first
high ramp operatively connected to flex the spring device from its
first position to its second position, and a second high ramp
operatively connected to cause the spring device to move from its
second position to its first position.
There are a number of advantages, features and objects achieved
with the present invention which are believed not to be available
in earlier related devices. For example, one advantage is that the
present invention provides a chair adjustment mechanism which is
quite simple, being constructed of only three molded synthetic
resin parts. Another object of the present invention is to provide
a chair adjustment mechanism that is relatively inexpensive. A
further advantage of the present invention is to provide a chair
adjustment mechanism which is reliable. Another feature of the
present invention is to provide a chair adjustment mechanism which
may be used to adjust the back of a chair, the seat of a chair or
the arms of a chair.
A more complete understanding of the present invention and other
objects, advantages and features thereof will be gained from a
consideration of the following description of a preferred
embodiment read in conjunction with the accompanying drawing
provided herein. The preferred embodiment represents an example of
the invention which is described here in compliance with Title 35
U.S.C. section 112 (first paragraph), but the invention itself is
defined by the attached claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a rear isometric view of an office chair showing the
chair adjustment mechanism in broken line used as a means for
adjusting the height of a chair back relative to a chair seat, for
example.
FIG. 2 is an exploded front isometric view of the chair adjustment
mechanism; and
FIG. 3 is an exploded rear isometric view of the chair adjustment
mechanism shown in FIG. 2.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
While the present invention is open to various modifications and
alternative constructions, the preferred embodiment shown in the
various figures of the drawing will be described herein in detail.
It is understood, however, that there is no intention to limit the
invention to the particular embodiment, form or example disclosed.
On the contrary, the intention is to cover all modifications,
equivalent structures and methods, and alternative constructions
falling within the spirit and scope of the invention as expressed
in the appended claims, pursuant to Title 35 U.S.C. section 112
(second paragraph).
An example of an office chair is illustrated in FIG. 1 and includes
a chair base 5 upon which is fixed a chair control to which is
attached a seat assembly 6, a back support 7 and a back assembly 8.
Mounted to the back support and the back assembly is a back height
adjustment mechanism 10 (shown in broken line).
Referring now to FIGS. 2 and 3, the back height adjustment
mechanism 10 is shown in more detail. The mechanism 10 is simple
and includes only three main elements. The first element is an
inner guide or base 12 that is provided with openings and suitable
nuts 14 such that it can be mounted in a fixed position to a chain
support, such as the support 7, FIG. 1. The second element is a
slide 16 that mounts to a back board by means of laterally spaced
side flanges 18 and fasteners (not shown). The third element is a
spring device 20 that is positioned between the base 12 and the
slide 16 in a space 19 formed therebetween and allows the slide to
selectively lock to the base so as to allow selective adjustment of
the height of the chair back relative to chair seat or the floor 11
on which the chair rests. It is understood that the mechanism 10
may also be used as a seat adjustment mechanism and as an arm
adjustment mechanism.
The slide 16, in addition to having the side flanges 18, also
includes two opposing channel tracks 21, 22 which are engaged by
the base 12 as will be explained below. The slide also has a center
panel 24 which includes three columns of ramps or cams, a central
column 26 of wide ramps and flanking outer columns 28, 30 of narrow
ramps. There are a series of five ramps 32, 34, 36, 38, 40 which
are used to determine the extended location of the slide 16 in
relation to the base 12. In turn this determines the location of a
chair back, in relation to a stationary support, such as the
support 7. The central column 26 also includes a first high ramp 42
and a second high ramp 43 which both project outwardly from the
center panel 24 to a greater distance than the first mentioned five
ramps 32, 34, 36, 38, 40. In a like and parallel fashion the two
outer rows of ramps 28, 30 each have a series of five smaller
ramps, such as ramps 50, 52, 54, 56, 58 in the outer column 28 and
the series of ramps 60, 62, 64, 66, 68 in the outer column 30.
Parallel to the first high ramp 42 are first outer high ramps such
as the high ramp 70 in the outer column 28 and the high ramp 72 in
the outer column 30. Parallel to the second high ramp 43 are second
high ramps 71, 73 in columns 28, 30, respectively.
Each of the high ramps 70, 71, 72, 73 extend outwardly a greater
distance in the space 19 from the center panel 24 than do the
earlier mentioned series of ramps in the outer columns. At the end
of the slide nearest to the ramps 42, 70, 72 are abutment walls 80,
82. As will be explained below, the various ramps operatively
engage the spring device in various ways to cause the spring to
selectively abut a center ramp and adjoining side ramps to lock the
slide relative to the base. The ramps also act as a cam to the cam
follower spring device so that the slide may move about a half an
inch to another ramp. When the slide reaches its fully extended
position certain ramps cam the spring device away from the series
of ramps so that the spring cannot make locking engagement. This
allows the slide to return in a single movement to its retracted
position. Other ramps act to reengage the spring with the series of
ramps to again allow the selective locking of the slide in relation
to the stationary base. Each ramp includes an abutment surface,
such as the abutment surface 84 of the ramp 40.
The slide may be made of any suitable material such as a synthetic
resin and that all of the various parts or portions thereof can be
molded at the same time as an integral item.
The spring device 20 includes the two legs 100, 101 with bottom
edges 102, 103, a central body 104 with a neck abutment surface
105, two shoulders 106, 108, two shoulder tips 109, 110, a head 111
and an elongated ledge 112. The spring device is also made of a
synthetic resin which may be molded as an integral element and is
capable of flexing so as to perform one of its various functions.
The neck abutment surface 105 selectively engages the series of
center ramps 32, 34, 36, 38, 40 of the slide, and the shoulder tips
109, 110 in a like manner engage parallel ramps in the columns 28,
30, so that when engaged the slide is locked relative to the
base.
The legs 100, 102 generally move along two longitudinal paths 114,
116 on the center panel 24 of the slide 16. Each path is formed
between the center column of ramps 26 and one of the outer columns
of ramps 28, 30. However, when the slide is at its fully extended
position relative to the base, the high ramps 42, 70, 72 engage the
central body 104 of the spring device 20 and cam or wedge the
central body shoulders 106, 108 under the hooks 120, 122 against
the biasing force provided by a deflection of the head 111 and the
bottom edges 102, 103 of the legs 100, 101 are moved to engage the
abutment walls 80, 82 at the ends of the longitudinal paths. This
prevents further extension of the slide relative to the base.
Once the spring device is engaged by the hooks, the slide can move
from the fully extended position all the way to the retracted
position without engaging any of the three series of ramps 32, 34,
36, 38, 40, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68. At the
retracted position, the shoulder tips 109, 110 engage the uppermost
high flanges 71, 73 and the neck abutment surface 105 engages the
center ramp 43. The high flanges 71, 73 push the shoulder tips 109,
110, and thereby the spring devices out of engagement with the
hooks 120, 122, and the head 111 biases the central body 104 back
to a position where the abutment surfaces 105, 109 and 110 again
are capable of selectively engaging the three series of ramps.
The base 12 is also made of a single piece of molded synthetic
resin and includes a center panel 124, two lateral walls 126, 127,
two laterally extending flanges 128, 129, the hooks 120, 122 and
abutment blocks 130, 131, 132. The lateral flanges 128, 129 engage
the channel tracks 21, 22 of the slide and thereby guide the slide
during its movement between a retracted position and a fully
extended position, a distance of about two and a half inches in six
increments or steps. The base has a space 134 on the center panel
124, adjacent the two hooks 120, 122 for the center body 104 of the
spring device 20, a space 136 for the head 111 of the spring device
and two parallel spaces 138, 140 for the legs 100, 101 of the
spring device. The spaced abutment blocks 130, 131, 132 have
abutment surfaces 133,135, 137 to engage the ledge 112 on the rear
side of the spring device to allow the spring device to seat or be
cradled within the base formed by the lateral walls 126, 127, the
center panel 124, the hooks 120, 122 and the abutment surfaces 133,
135, 137 in the spaces 134, 136, 138, 140. The two hook projections
120, 122 have bottom ledges 140, 142. These bottom edges make
contact with the shoulders 106, 108.
The slide is about six inches long and four inches wide. The base
is about five inches long and about two and a half inches wide. The
space 19 is roughly five-sixteenth inches deep, while the spring
device is about two inches high and one and three-quarter inches
wide. Change in these dimensions are still considered part of the
invention.
Operation of the chair adjustment mechanism when used for back
height adjustment can now be appreciated with reference to the
figures of the drawing. Beginning with the chair back in the down,
fully retracked position, the shoulder tips 109, 110 engage the
large outer ramps 71, 73 and the neck surface 105 engages the ramp
43. Further, movement disengages the shoulders 106, 108 from the
hooks 120, 122. Thereafter the slide may be raised or extended
anywhere within the approximately two and a half inches and six
steps determined by the positions of the center ramps 32, 34, 36,
38, 40, and corresponding outer ramps, as desired by the chair
user. As each center ramp is passed, the center body 104 is flexed
relative to the head 111 until the neck surface 105 passes the ramp
at which point the center body 104 snaps back into position so that
should the slide attempt a reverse movement, the neck surface 105
and the shoulder tips 109, 110 will abut one of the center ramps
and corresponding outer ramps and prevent any movement. This locks
the back of the chair relative to the seat and may be thought of as
the first abutment.
When the last ramp 40 of the five middle ramps is passed further
extension of the slide causes the center body 104 to be deflected
against the base so that the shoulders 106, 108 engage under the
hooks 120, 122 and the leg edges 102, 103 engage the abutment walls
80, 82. This is the second and third abutments. The slide may now
be fully retracted in one movement because the spring device is
snug against the base and out of the way of the ramps. This
condition is maintained until the spring device comes into contact
with the uppermost center ramp 43 (in terms of position shown in
FIG. 3) and the parallel aligned outer ramps 71, 73. These push the
spring device from engagement with the hooks and reset the spring
device to allow the slide to be positioned in any one of the six
vertical positions mentioned. This is referred to as the fourth
abutment.
The above specification describes in detail a preferred embodiment
of the present invention. Other examples, embodiments,
modifications and variations will, under both the literal claim
language and the doctrine of equivalents, come within the scope of
the invention defined by the appended claims. For example, making
slight modifications to the spring device or to its shape, the
shape of the ramps on the slide or the hooks on the base are
considered equivalent structures and will also come within the
literal language of the claims. Still, other alternatives will also
be equivalent as will many new technologies. These are all
considered equivalent structures and will also come within the
literal language of the claims so other alternatives will also be
equivalent as will many new technologies. There is no desire or
intention here to limit in any way the application of the doctrine
of equivalents nor to limit or restrict the scope of the
invention.
* * * * *